Fuzzy Control Research About EEV Of Automobile Waste Heat Driven Air-Condition

Air conditioning systems, providing comfort for the automobile space, will increase the energy consumption of the engine inevitably. So improving the energy efficiency of air conditioning is an important issue. The main work of this paper are shown as follows:1. A hybrid refrigeration cycle driven by waste heat for automobile air conditioning system was proposed in this paper. The hybrid compressor and ejector refrigeration system was put forward for the advantage of ejector which can improve the evaporator pressure without expending mechanical energy. The hybrid automotive air conditioning refrigerating system can be controlled in three work modes:the compression refrigeration system mode, injection mode and mixed mode, and the control of the modes could improve the systematic energy efficiency ratio and thus reduce the energy consumption of automobiles.2. A fuzzy control program for the superheated levels of the evaporator in hybrid refrigeration cycle system was designed in this paper. Because it is difficult to determine the accurate mathematics model of refrigeration cycle system for its nonlinear time-varying dynamic property. And the performance of refrigeration system can be seriously influenced by a slight change of superheated level in evaporator. So a suitable control scheme of superheated levels was designed corresponding to the theory of fuzzy controlling.3. The experiment device of the hybrid refrigeration control system was designed by the linking between Lab VIEW and MATLAB for the real-time communication. Sensors and PCI-1711 data acquisition card were used to collect the line parameters information, such as temperature, pressure, refrigerant flow rate and power. And LabVIEW software control system was used to display, analyze and process the acquisition signals for the controlling of compressor, electronic expansion valve and inverter.4. The minimum steady-state superheated curve and the evaporator superheated experimental model were established in the experimental research. The relationship between the evaporator superheated levels and the evaporation temperature was studied under different working conditions, and the minimum steady-state superheated curve of the electronic expansion valve was calculated; This paper also studied the relationship among the evaporator static gain, time constant, delay time and the evaporation temperature, and established the superheated experimental model for evaporator and electronic expansion valve under the dynamic experimental response of the evaporator superheated levels and the electronic expansion valve opening. It can control the evaporator superheated level, adjust the opening of the electronic expansion valve, and realize the stability controlling of superheat of the refrigeration system according to the designed fuzzy controller. The simulation results showed that the proposed fuzzy control is superior to the traditional PID control.